Method and Device for Quantization of Linear Prediction Coefficient and Method and Device for Inverse Quantization

1. A quantization apparatus for encoding of an audio signal, the quantization apparatus comprising: a first quantization module, implemented by at least one processor, configured to quantize line spectral frequency (LSF) coefficients of the audio signal without an inter-frame prediction; and a second quantization module, implemented by the at least one processor, configured to quantize the LSF coefficients with the inter-frame prediction, wherein the first quantization module comprises: a first quantization part configured to quantize an audio signal to generate a first quantization signal; and a third quantization part configured to quantize a first quantization error signal generated from the first quantization signal and the audio signal, wherein the second quantization module comprises: an inter-frame predictor configured to generate a prediction signal to predict the audio signal; a second quantization part configured to quantize a prediction error signal generated from the prediction signal and the input signal, to generate a second quantization signal; and a fourth quantization part configured to quantize a second quantization error signal generated from the prediction error signal and the second quantization signal, wherein the first quantization part and the second quantization part comprise a trellis structured vector quantizer which allocates LSF sub-vectors to each stage of the trellis structured vector quantizer, wherein the third quantization part and the fourth quantization part share a codebook, and wherein a scaling is performed on a signal to be input to the third quantization part by using scaling factors determined based on the signal to be input to the third quantization part and a signal to be input to the fourth quantization part.

2. The quantization apparatus of claim 1 , further comprising a selection unit, implemented by at least one processor, for selecting, in an open-loop manner, one of the first quantization module and the second quantization module based on the prediction error signal.

3. The quantization apparatus of claim 1 , wherein the third quantization part and the fourth quantization part are vector quantizers.

4. The quantization apparatus of claim 1 , wherein a coding mode of the audio signal is a voiced coding (VC) mode.

5. A quantization method for encoding of an audio signal, the quantization method comprising: selecting, in an open-loop manner, one of a first quantization module configured to quantize line spectral frequency (LSF) coefficients of the audio signal without an inter-frame prediction and a second quantization module configured to quantize the LSF coefficients with the inter-frame prediction; and quantizing an audio signal by using the selected one of the first quantization module and the second quantization module, wherein the first quantization module, implemented by at least one processor, comprises: a first quantization part configured to quantize the audio signal to generate a first quantization signal; and a third quantization part configured to quantize a first quantization error signal generated from the first quantization signal and the audio signal, wherein the second quantization module, implemented by the at least one processor, comprises: an inter-frame predictor configured to generate a prediction signal to predict the audio signal; a second quantization part configured to quantize a prediction error signal generated from the prediction signal and the audio signal, to generate a second quantization signal; and a fourth quantization part configured to quantize a second quantization error signal generated from the prediction error signal and the second quantization signal, wherein the first quantization part and the second quantization part comprise a trellis structured vector quantizer which allocates LSF sub-vectors to each stage of the trellis structured vector quantizer, wherein the third quantization part and the fourth quantization part share a codebook, and wherein a scaling is performed on a signal to be input to the third quantization part by using scaling factors determined based on the signal to be input to the third quantization part and a signal to be input to the fourth quantization part.

6. The quantization method of claim 5 , wherein the selecting is based on the prediction error signal.